1. Field of the Invention
This invention relates to a heat transfer recording apparatus and a facsimile apparatus for transferring the ink of an ink sheet to a recording medium to thereby effect recording of images on the recording medium.
The term "heat transfer recording apparatus" covers, in addition to the facsimile apparatus, for example, an electronic typewriter, a copying apparatus, a printer, etc.
2. Related Background Art
Generally, a heat transfer printer uses an ink sheet comprising a base film having heat-meltable (or heat-sublimating) ink applied thereto, and selectively heats the ink sheet corresponding to an image signal by a thermal head and transfers the melted (or sublimated) ink to recording paper to thereby accomplish image recording. Generally, this ink sheet is one in which the ink is completely transferred to the recording paper by one time of image recording (a so-called one-time sheet) and therefore, after the termination of the recording of one character or one line, it has been necessary to convey the ink sheet by an amount corresponding to the length of the record, and then reliably bring the unused portion of the ink sheet to a recording position. Therefore, the amount of ink sheets used is increased, and this has led to the tendency that as compared with an ordinary thermosensitive printer for effecting recording on thermosensitive paper, the running cost of the heat transfer printer becomes high.
In order to solve such a problem, as seen in U.S. Pat. No. 4,456,392, Japanese Laid-Open Patent Application No. 58-201686 and Japanese Patent Publication (examined) No. 62-58917, there have been proposed heat transfer printers in which recording paper and an ink sheet are conveyed with a velocity difference provided therebetween. As is described in the aforementioned publications, an ink sheet capable of plural (n) times of image recording (a so-called multiprint sheet) is known. If such ink sheet is used, when a record length L is to be continuously recorded, recording can be accomplished with the conveyance length of the ink sheet which is conveyed after or during each image recording being made smaller than that length L (L/n: n&gt;1). Thereby, the efficiency of use of the ink sheet increases to n times that before, and a reduction in the running cost of the heat transfer printer can be expected. This recording system will hereinafter be referred to as multiprint.
However, in the multiprint using such an ink sheet, as seen in the aforementioned publications, the distance by which the ink sheet is conveyed relative to the recording paper is always set to the same length. This means that the number of multiprints is always fixed, and for example, when use is made of an ink sheet in which the number of times of multiprint is set to five times, if the number of times of multiprint by the heat transfer printer is greater than five times, the recording density will become thin, but if the number of times of multiprint is less than five times, the recording density will become great, while the amount of the ink sheet used will increase. Also, in the future, with the advance of technology, it is expected that an ink sheet capable of further increasing the number of times of multiprint or an ink sheet capable of multiprint at various number of times is developed. Therefore, there has been desired the realization of a heat transfer printer in which the number of times of multiprint corresponding to the frequency of use of the ink sheet can be set and a facsimile apparatus using such a heat transfer printer. Also, when an ink sheet capable of a greater number of times of multiprint is replaced with an ink sheet capable of a lesser number of times of multiprint, multiprint will be executed at the original number of times until the frequency of repeated use of that replacing ink sheet is input. This has led to the undesirable possibility that when the ink sheet is newly replaced with an ink sheet permitting a lesser frequency of repeated use, the recording density thereof becomes lower.